21352140 has 48 divisors (see below), whose sum is σ = 66430560. Its totient is φ = 5693760.

The previous prime is 21352139. The next prime is 21352183. The reversal of 21352140 is 4125312.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19231 + ... + 20310.

It is an arithmetic number, because the mean of its divisors is an integer number (1383970).

Almost surely, 2^21352140 is an apocalyptic number.

21352140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21352140 is an abundant number, since it is smaller than the sum of its proper divisors (45078420).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21352140 is a wasteful number, since it uses less digits than its factorization.

21352140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39559 (or 39551 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21352140 is about 4620.8375864122. The cubic root of 21352140 is about 277.4259846430.

Adding to 21352140 its reverse (4125312), we get a palindrome (25477452).

The spelling of 21352140 in words is "twenty-one million, three hundred fifty-two thousand, one hundred forty".